Present filament winding systems generally consist of winding fibrous rovings or tows impregnated with a thermosetting resin in a helical pattern in a number of superimposed layers onto a mandrel to produce a tubular article. In most types of filament winding operations, the rovings pass through a delivery eye or from a delivery roller across an air space onto the part. In that type of system, tows cannot be added or deleted during operation to adjust to the varying contours of the part being wound. Furthermore, that type of system is limited to geodesic or natural path fiber patterns. Conventional tape laying systems generally provide positioning of the rovings on flat or slightly contoured surfaces, however, these systems cannot wind two dimensional contours without fiber gaps or overlaps unless an impracticably narrow band is employed. Tape layers cannot vary the band width without terminating the entire band.
The inability to alter bandwidth while winding parts with non-uniform cross-section, such as fuselages, tapered wing skins, domes or missile nose cones, results in overlapping or gapping of the winding band. The inability to accurately place fiber at the optimum angle results in heavier than necessary designs. In some cases this results in a design which cannot be automated and or is less costly and no heavier if designed in metal.
U.S. Pat. No. 4,867,834 discloses a filament winding system which effectively overcomes disadvantages of prior systems. The system U.S. Pat. No. 4,867,834 however, involves an arrangement in which all of the tows are transported through the head in a single plane. Additionally, in that arrangement the tows are cut by a solenoid actuated knife which travels transversely across a slot. Addition of cut tows relied on the remaining tows providing the driving force. Therefore, only one half of the tows could be terminated.
It would be desirable if means could be provided to modify the type of assembly described in Ser. No. 163,141 so as to permit a greater number of tows to be handled, while maintaining a compact head and while minimizing the spread of the tows coming into the head. It is also desirable to terminate plies at specified locations like a conventional tape layer.